Sen. Kamala Harris, D-CA, aggressively questioned the attorney general on the so-called longstanding DOJ policy that prevents him from speaking publicly about Trump. The heated exchange peaked when a Senate Republican interrupted, telling Harris to "let him answer."

Sen. Kamala Harris is interrupted by Sen. Burr while pressing AG Sessions during tense line of questions https://t.co/Qypc6PHk1P

Connecticut Sen. Richard Blumenthal called for sessions to be subpoenaed.

UPDATE 4:05 PM: Sessions answers why he's giving his non-answers

Senator Martin Heinrich, D-New Mexico, accuses Sessions of impeding the investigation by not answering questions about his conversations with Trump, specifically whether he and the president discussed pardons.

Sessions, who had requested his hearing be public, responded by saying he wasn’t invoking executive privilege and that he was “protecting the president's constitutional right by not giving it away before he has a chance to review it.”

Senator Ron Wyden, D-Oregon, pressed Sessions over Comey's assertion last week that there were "problematic matters" relating to Sessions' recusal.

Sessions: "There are none. I can tell you this is a secret innuendo being leaked about me and I don’t appreciate it..."

Wyden: "That answer in my view doesn’t pass the smell test."

Attorney General Jeff Sessions reads from a statute about his recusal while testifying on Capitol Hill in Washington, Tuesday, June 13, 2017, before the Senate Intelligence Committee hearing about his role in the firing of James Comey, his Russian contacts during the campaign and his decision to recuse from an investigation into possible ties between Moscow and associates of President Donald Trump. (AP Photo/Alex Brandon)

UPDATE 3:38 PM: Sessions says point blank that no one in the Trump administration has asked him to do anything "illegal" or "improper" as attorney general.

UPDATE 3:25 PM: Sessions says he's confident in Mueller

Democratic Senator Mark Warner asked Sessions if he had confidence in special counsel Robert Mueller's ability to oversee the investigation into alleged Russian election interference. Warner's question comes after reports the president was considering directing Deputy Attorney General Rod Rosenstein to fire Mueller.

"I have confidence in Mr. Mueller, but I am not going to discuss any hypotheticals,” Sessions told Warner.

Testifying before the same Senate Appropriations subcommittee, Rosenstein said earlier Tuesday he would not fire Mueller without good cause.

When asked by Warner if he would take any actions to have Mueller fired, Sessions said: Asked if he would take any actions to have special counsel fired, Sessions says, "I wouldn't think that would be appropriate for me to do."

I did not recuse myself from defending my honor against scurrilous and false allegations.

UPDATE 3:07 PM: Sessions appeals to his former colleagues

Prior to being tapped as attorney general, Sessions spent two decades in the Senate.

UPDATE 2:57 PM:

Sessions denies collusion

Sessions says he wasn't aware of or part of collusion with the Russian government, calling the suggestion "an appalling and detestable lie."

Sessions also denied meeting for a third time with Russian officials. Late last month, CNN reported Sessions met with Russian officials at the Mayflower Hotel in D.C. during the presidential campaign.

Jeff Sessions described accusations of Russia collusion as 'appalling and detestable'

In March, Sessions recused himself from the investigation into contacts between Russia and the Trump campaign after it emerged he had met twice last year with Russia's ambassador to the U.S.

"I am hopeful that members will focus their questions today on the Russia investigation and not squander this opportunity by taking political or partisan shots," Burr told the committee.

Attorney General Jeff Sessions is testifying in an open hearing before the Senate Intelligence Committee. Senators are expected to challenge Sessions over his role in former FBI Director James Comey's firing, his recusal from the Russia investigation and his meetings with Russian Ambassador Sergey Kislyak.

Just last week, Comey told the same committee he had "problematic" information about Sessions' actions before the attorney general recused himself from the Russia investigation.

Sessions' testimony follows reports that he offered to resign as attorney general amid tensions with President Trump -- an offer the president refused. According to The New York Times, Sessions made the offer after telling Trump he needed the freedom to do his job.